CVE-2026-34778 | Electron: Service worker can spoof executeJavaScript IPC replies

Electron is a framework for writing cross-platform desktop applications using JavaScript, HTML and CSS. Prior to versions 38.8.6, 39.8.1, 40.8.1, and 41.0.0, a service worker running in a session could spoof reply messages on the internal IPC channel used by webContents.executeJavaScript() and related methods, causing the main-process promise to resolve with attacker-controlled data. Apps are only affected if they have service workers registered and use the result of webContents.executeJavaScript() (or webFrameMain.executeJavaScript()) in security-sensitive decisions. This issue has been patched in versions 38.8.6, 39.8.1, 40.8.1, and 41.0.0.

Published: 2026-04-04 Last update: 2026-04-20 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-34778 is rated Low Risk (24.4/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.01%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-34778

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-04-04 — 0.01% —

Full EPSS history (1 record total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-34778

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.9 3.1 MEDIUM
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:H/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
 1.6 4.2 [email protected]
6.5 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
 2.8 3.6 [email protected]

Weakness enumeration for CVE-2026-34778

GitHub Security Advisory for CVE-2026-34778

GHSA-xj5x-m3f3-5x3h · Severity: medium · Ecosystem: npm — Electron: Service worker can spoof executeJavaScript IPC replies

OS Trackers for CVE-2026-34778

vendor priority summary link
redhat medium — https://access.redhat.com/security/cve/CVE-2026-34778

Affected software / configurations for CVE-2026-34778

Vendor Product Version Raw CPE
electronjs electron < 38.8.6 cpe:2.3:a:electronjs:electron:*:*:*:*:*:node.js:*:*
electronjs electron >= 39.0.0, < 39.8.1 cpe:2.3:a:electronjs:electron:*:*:*:*:*:node.js:*:*
electronjs electron >= 40.0.0, < 40.8.1 cpe:2.3:a:electronjs:electron:*:*:*:*:*:node.js:*:*
electronjs electron 41.0.0 cpe:2.3:a:electronjs:electron:41.0.0:alpha1:*:*:*:node.js:*:*
electronjs electron 41.0.0 cpe:2.3:a:electronjs:electron:41.0.0:alpha2:*:*:*:node.js:*:*
electronjs electron 41.0.0 cpe:2.3:a:electronjs:electron:41.0.0:alpha3:*:*:*:node.js:*:*
electronjs electron 41.0.0 cpe:2.3:a:electronjs:electron:41.0.0:alpha4:*:*:*:node.js:*:*
electronjs electron 41.0.0 cpe:2.3:a:electronjs:electron:41.0.0:alpha5:*:*:*:node.js:*:*
electronjs electron 41.0.0 cpe:2.3:a:electronjs:electron:41.0.0:alpha6:*:*:*:node.js:*:*
electronjs electron 41.0.0 cpe:2.3:a:electronjs:electron:41.0.0:beta1:*:*:*:node.js:*:*
electronjs electron 41.0.0 cpe:2.3:a:electronjs:electron:41.0.0:beta2:*:*:*:node.js:*:*
electronjs electron 41.0.0 cpe:2.3:a:electronjs:electron:41.0.0:beta3:*:*:*:node.js:*:*
electronjs electron 41.0.0 cpe:2.3:a:electronjs:electron:41.0.0:beta4:*:*:*:node.js:*:*
electronjs electron 41.0.0 cpe:2.3:a:electronjs:electron:41.0.0:beta5:*:*:*:node.js:*:*
electronjs electron 41.0.0 cpe:2.3:a:electronjs:electron:41.0.0:beta6:*:*:*:node.js:*:*
electronjs electron 41.0.0 cpe:2.3:a:electronjs:electron:41.0.0:beta7:*:*:*:node.js:*:*
electronjs electron 41.0.0 cpe:2.3:a:electronjs:electron:41.0.0:beta8:*:*:*:node.js:*:*

References for CVE-2026-34778

cvelogic Threat Intelligence